我们在服务器上运行了几个redis实例.还有多个Web层服务器连接到那些同时遇到停顿的实例.
我们当时正在进行数据包捕获,确定在TX和RX流量中存在停顿,如下面的wireshark IO图：
redis调用有一个相关的峰值,但我怀疑这是一个影响,而不是由于时滞造成的原因：
使用15 / s采样间隔(这是作为计数器收集),平均有136个内存分配停顿：
虽然上面看起来很正常,但是有两个连续的数据点使得它与图中看到的其他300个峰值相比变得异常.
内存压缩失败和压缩失速也有相关的峰值：
虽然我在这里有丰富的内存信息,但我的Linux内存知识还不够深入,无法真正假设一个好的故事,将所有这些信息汇总在一起来解释失速.任何具有深入Linux内存知识(也许是深度内存知识)的人都可以将这些信息结合在一起吗？
我们以15秒的间隔从/ proc / vmstat收集所有统计信息,因此如果您认为可能会添加任何数据,请执行此操作.我刚刚选择了似乎有趣的活动,特别是alloc stall,numa迁移和压缩停顿/失败.总计如下,并涵盖20天的正常运行时间：
[kbrandt@ny-redis01: ~] uptime 21:11:49 up 20 days,20:05,8 users,load average: 1.05,0.74,0.69 [kbrandt@ny-redis01: ~] cat /proc/vmstat nr_free_pages 105382 nr_alloc_batch 5632 nr_inactive_anon 983455 nr_active_anon 15870487 nr_inactive_file 12904618 nr_active_file 2266184 nr_unevictable 0 nr_mlock 0 nr_anon_pages 16361259 nr_mapped 26329 nr_file_pages 15667318 nr_dirty 48588 nr_writeback 0 nr_slab_reclaimable 473720 nr_slab_unreclaimable 37147 nr_page_table_pages 38701 nr_kernel_stack 987 nr_unstable 0 nr_bounce 0 nr_vmscan_write 356302 nr_vmscan_immediate_reclaim 174305 nr_writeback_temp 0 nr_isolated_anon 0 nr_isolated_file 32 nr_shmem 423906 nr_dirtied 3071978326 nr_written 3069010459 numa_hit 1825289996 numa_miss 3360625955 numa_foreign 3360626253 numa_interleave 64798 numa_local 1856473774 numa_other 3329442177 workingset_refault 297175 workingset_activate 24923 workingset_nodereclaim 0 nr_anon_transparent_hugepages 41 nr_free_cma 0 nr_dirty_threshold 3030688 nr_dirty_background_threshold 1515344 pgpgin 25709012 pgpgout 12284206511 pswpin 143954 pswpout 341570 pgalloc_dma 430 pgalloc_dma32 498407404 pgalloc_normal 8131576449 pgalloc_movable 0 pgfree 8639210186 pgactivate 12022290 pgdeactivate 14512106 pgfault 61444049878 pgmajfault 23740 pgrefill_dma 0 pgrefill_dma32 1084722 pgrefill_normal 13419119 pgrefill_movable 0 pgsteal_kswapd_dma 0 pgsteal_kswapd_dma32 11991303 pgsteal_kswapd_normal 1051781383 pgsteal_kswapd_movable 0 pgsteal_direct_dma 0 pgsteal_direct_dma32 58737 pgsteal_direct_normal 36277968 pgsteal_direct_movable 0 pgscan_kswapd_dma 0 pgscan_kswapd_dma32 13416911 pgscan_kswapd_normal 1053143529 pgscan_kswapd_movable 0 pgscan_direct_dma 0 pgscan_direct_dma32 58926 pgscan_direct_normal 36291030 pgscan_direct_movable 0 pgscan_direct_throttle 0 zone_reclaim_Failed 0 pginodesteal 0 slabs_scanned 1812992 kswapd_inodesteal 5096998 kswapd_low_wmark_hit_quickly 8600243 kswapd_high_wmark_hit_quickly 5068337 pageoutrun 14095945 allocstall 567491 pgrotated 971171 drop_pagecache 8 drop_slab 0 numa_pte_updates 58218081649 numa_huge_pte_updates 416664 numa_hint_faults 57988385456 numa_hint_faults_local 57286615202 numa_pages_migrated 39923112 pgmigrate_success 48662606 pgmigrate_fail 2670596 compact_migrate_scanned 29140124 compact_free_scanned 28320190101 compact_isolated 21473591 compact_stall 57784 compact_fail 37819 compact_success 19965 htlb_buddy_alloc_success 0 htlb_buddy_alloc_fail 0 unevictable_pgs_culled 5528 unevictable_pgs_scanned 0 unevictable_pgs_rescued 18567 unevictable_pgs_mlocked 20909 unevictable_pgs_munlocked 20909 unevictable_pgs_cleared 0 unevictable_pgs_stranded 0 thp_fault_alloc 11613 thp_fault_fallback 53 thp_collapse_alloc 3 thp_collapse_alloc_Failed 0 thp_split 9804 thp_zero_page_alloc 1 thp_zero_page_alloc_Failed 0
还有所有/ proc / sys / vm / *设置如果有帮助：
***/proc/sys/vm/admin_reserve_kbytes*** 8192 ***/proc/sys/vm/block_dump*** 0 ***/proc/sys/vm/dirty_background_bytes*** 0 ***/proc/sys/vm/dirty_background_ratio*** 10 ***/proc/sys/vm/dirty_bytes*** 0 ***/proc/sys/vm/dirty_expire_centisecs*** 3000 ***/proc/sys/vm/dirty_ratio*** 20 ***/proc/sys/vm/dirty_writeback_centisecs*** 500 ***/proc/sys/vm/drop_caches*** 1 ***/proc/sys/vm/extfrag_threshold*** 500 ***/proc/sys/vm/hugepages_treat_as_movable*** 0 ***/proc/sys/vm/hugetlb_shm_group*** 0 ***/proc/sys/vm/laptop_mode*** 0 ***/proc/sys/vm/legacy_va_layout*** 0 ***/proc/sys/vm/lowmem_reserve_ratio*** 256 256 32 ***/proc/sys/vm/max_map_count*** 65530 ***/proc/sys/vm/memory_failure_early_kill*** 0 ***/proc/sys/vm/memory_failure_recovery*** 1 ***/proc/sys/vm/min_free_kbytes*** 90112 ***/proc/sys/vm/min_slab_ratio*** 5 ***/proc/sys/vm/min_unmapped_ratio*** 1 ***/proc/sys/vm/mmap_min_addr*** 4096 ***/proc/sys/vm/nr_hugepages*** 0 ***/proc/sys/vm/nr_hugepages_mempolicy*** 0 ***/proc/sys/vm/nr_overcommit_hugepages*** 0 ***/proc/sys/vm/nr_pdflush_threads*** 0 ***/proc/sys/vm/numa_zonelist_order*** default ***/proc/sys/vm/oom_dump_tasks*** 1 ***/proc/sys/vm/oom_kill_allocating_task*** 0 ***/proc/sys/vm/overcommit_kbytes*** 0 ***/proc/sys/vm/overcommit_memory*** 1 ***/proc/sys/vm/overcommit_ratio*** 50 ***/proc/sys/vm/page-cluster*** 3 ***/proc/sys/vm/panic_on_oom*** 0 ***/proc/sys/vm/percpu_pagelist_fraction*** 0 ***/proc/sys/vm/scan_unevictable_pages*** 0 ***/proc/sys/vm/stat_interval*** 1 ***/proc/sys/vm/swappiness*** 60 ***/proc/sys/vm/user_reserve_kbytes*** 131072 ***/proc/sys/vm/vfs_cache_pressure*** 100 ***/proc/sys/vm/zone_reclaim_mode*** 0
更新：
有一个thp_split在时间上接近：
